This description relates to Nano-Electro-Mechanical Systems (NEMS) and Complementary Metal Oxide Semiconductor (CMOS) circuitry for detection of chemical and biological agents, referred to as ligands, with sensitivity down to one molecule. NEMS are sensors or actuators that have critical dimensions in nanometer range.
Sensitive detection of gases such as explosive vapors and environmental pollution in ambient environment normally requires sophisticated and expensive instrumentation. Such detection is usually carried out with optical spectrometers or quadrupole, ion trap or time of flight mass spectrometers.
Detection of biological agents is typically performed in liquids using chemical or biological assays that rely on the detection of intrinsic or covalently-attached fluorescent or ultraviolet labels, chemical or electrochemical luminescence, or radioactive labels. These approaches often limit the sensitivity of the assay method and also require expensive equipment. Detection of biological agents can be also performed without labeling with techniques such as surface plasmon resonance, waveguide resonance, electrochemical methods, but such techniques have typically lower sensitivity than labeled methods and similar limitations.
None of these conventional techniques is sufficiently sensitive to detect single molecules or have sufficient resolution to differentiate between molecules that differ in mass by several atomic mass units. The equipment used is not portable or easily operated by the non-specialist. Therefore, these techniques are unsuitable for many personalized wellness, personalized medical and other mobile applications. Portable, robust, easy-to-use clinical measurements enable individuals and medical facilities such as doctor's offices, pharmacies, and diagnostic laboratories to obtain clinically meaningful information reliably and at low cost. There is need to realize detection with the simple devices that have extreme sensitivity for chemical or biological molecules (such as proteins), and small biological agents (e.g., viruses and bacteria), with very inexpensive device.